The invention relates to devices for hoisting boats on boards ships and for lowering them into the water from these ships.
It concerns more especially those of these hoisting devices which comprise a ramp coupled to the rear of the ship for pivoting about a horizontal transverse axis related to the ship, which ramp is adapted for supporting the boats between the water and a reception zone provided on board the ship.
In known embodiments of these hoisting devices, the ramp is formed by a solid flat hatch, which has a number of drawbacks and particularly the following:
the drag resistance opposing the advance of the ship when the rear portion of the hatch is immersed in the water is relatively high, so that boat hoisting and lowering operations can only be carried out when the ship is stopped or is advancing at a slow speed,
the convex shape of the lower faces of the boat hulls is not suitable for supporting and guiding these hulls by means of solid flat hatches and said faces are damaged when sliding over such hatches,
the support in question frequently requires previous upward retraction of the propellers and of their drive motor.